Process for chemically texturing polyester fibers

ABSTRACT

Process for chemically texturing fibers, particularly polyester fibers, by treatment of the fibers with treating agents in aqueous solution of perfluorinated or perfluorochlorinated ketone hydrates which cause differential swelling to occur between the skin and core of the fibers.

United States Patent [72] Inventors Robert W. Lenz [56] R f en e CfiiidAmber; UNITED STATES PATENTS Leo Barish, Sharon; Virginia L. Lyons,

3,374,273 3/1968 Cunningham 260/593 Arlington, all of Mass.

3,129,053 4/ 1964 Castle 8/93 21 Appl. No. 718,020

3,084,020 4/1963 Toos11.... 8/ 130.1 [22] Filed Apr. 1, 1968 2,870,21 11/1959 M11ler.... 260/593 [45] Pmmed 1971 2 897 042 7/1959 l-leiks 8/1301 [73] Assign Amedchemiml co on New York, N.Y. Primary Examiner-GeorgeF. Lesmes Assistant Examiner-B. Bettis Attorney-Jay P. Friedenson [54]PROCESS FOR CHEMICALLY TEXTURING POLYESTER FIBERS 15 c 4 Drawing Figs.

[52] US. CL 8/l30.1, ABSTRACT: Process for chemically texturing fibers,particu- 8/ 1 14.5, 8/1 15.5 larly polyester fibers, by treatment of thefibers with treating [51] Int. D0611: 13/08 agents in aqueous solutionof perfiuorinated or per- [50] Field 01 Search 8/ 130.1,fluorochlorinated ketone hydrates which cause differential swelling tooccur between the skin and core of the fibers.

E ECT OF SFK EH 0 TRE MF U ON THE SlNGLl LOAD Tn RUPTHHF PROPERTIES OFDACRON 70-IORO2-55 MULT FILAMENT POL (1.5 1% 1L1".

TENACITYKQRAMS PER UENIER) A |0% CONTRACT/ON 1 5 (20% CONTRACTIF N 135%CONTRACTION] (4061 CONTRACTVON] PATENTEDIIIIV 1s l97| SHEET 2 BF 2DACRON FILAMENT IN IO I 6FK-3H O WATER, 7 MINUTES 3 G I F DAC RONFILAMENT IN IO I GFK -3H O WATER, I8 MINUTES- VIRGINIA L. LYONS ATTORNEY BACKGROUND OF THE INVENTION Fabrics made from syntheticcontinuous filament yarns are normally smooth, dense lustrous, and lookand feel coldand metallic, making them unacceptable for many textilepurposes. However, because of their relatively low cost the use ofcontinuous filament yarns in fabrics is attractive. Thus syntheticcontinuous filament yarns are often textured to give them softercharacteristics more like natural fibers. Such texturing is done byinserting into the filaments of the yarn a complexity of randompermanent bends, loops or crimps. Use of such yarns produces fabricswhich are less smooth and uniform than those made with untextured yarnsbut which are soft, lofty, dull, stretchy, warm and generally approachthe look and feel of fabrics made from natural fibers.

Many techniques have been devised for the purposes of texturing yarnfilaments or fibers in order to achieve the above results. However, suchtechniques have not been notably successful for texturing polyesterfibers. For example, the socalled stuffer box method, which can be usedto texture nylon and acrylic fibers, is not successful with polyesterfibers.

One of the most successful methods of texturing polyester fibers is theso-called false twist method, which is applicable I only withdifficulty. in this method a continuous filament is twisted and thetwist is set by the use of heat or steam. The twist is then removed fromthe filament, for example while winding the filament on a spool. Whenyarn and fabric are made from such treated filaments the filaments tendto return to their twisted configuration, thus giving the fabric thedesired texture characteristics. However, in addition to being difficultto practice on polyesters, this method has the disadvantage that itimparts stretch but not bulk to the yam. Also, false-twisted yarnscontain a residual torque and must be used in plys to prevent distortionof the fabric.

For the above reasons it is highly desirable to develop new and improvedprocesses for texturing polyester fibers.

SUMMARY OF THE INVENTION It is an object of this invention to provide anew and improved method of texturing fibers, particularly polyesterfibers.

It is also an object of this invention to provide a chemical method fortexturing fibers, particularly polyester fibers.

It is a further object of this invention to provide a method fortexturing polyester fibers which imparts bulk to yarn and which resultsin fibers which do not possess residual torque.

Other and further objects of this invention will be obvious to thoseskilled in the art from a reading of the following specification andclaims.

The process of this invention comprises inducing fiber curling bytreating the fibers, particularly polyester fibers, with treating agentswhich are solvents having a diflusion rate such that the solvent causesthe skin or outer annular portion of the fiber to swell differentiallywith respect to the core of the fiber. Although this invention isparticularly described with regard to its application to polyesterfibers, it can be used on any natural or synthetic fiber which exhibitsthe abovementioned differential swelling. The process of this inventionmore particularly comprises inducing such fiber curling in polyesterfibers by treating them with an aqueous solution of a treating agentselected from the group consisting of perfluorinated ketone hydrates,perfluorochlorinated ketone hydrates and phenol. Perfiuorinated acetoheand perfiuorochlorinated acetone hydrates have been found to beparticularly useful in this process. Even more particularly,hexafluoroacetone trihydrate (CF COCF 'Hfl),pentafluoromonochloroacetone trihydrate (CF CoCF C1'3H andtetrafluorodichloroacetone dihydrate (CCIF,COCC1F,'2 rH,0) have provedto be particularly useful textile-treating agents, as has phenol.

Phenol is, of course, a known and widely available compound.

' Woolf, the disclosure of which Hexafluoroacetone 2 I trihydrate andpentafluoromonochloroacetone trihydrate are known materials which areand the preparation of which are described in detail in copending,commonly assigned U.S. application No. 591,034, filed Oct. 31, 1966, byW. J. Cunningham and C. application is incorporated herein by reference.Briefly, hexafluoroacetone trihydrate and 'pentafluoromonochloroacetonetrihydrate can be made by heating the corresponding monohydrate compoundto volatilize therefrom constituents boiling below about 105 C. atatmospheric pressure.

Tetrafluorodichloroacetone dihydrate is a known material which is andthe preparation of which is described in commonly assigned U.S. Pat. No.2,870,211, the disclosure of which is incorporated herein' by reference.Briefly, tetrafluorodichloroacetone dihydrate can be made by heating aliquor containing tetrafluorodichloroacetone and water to distilltherefrom volatile constituents boiling below about 106 C., heating theremaining solution to vaporize'same, and condensing the vapors.

In treatment according to this invention,the treating solution can beapplied to the fibers by dipping, spraying, vapor phase swelling or anyother contact technique. When it is desired to cease treatment, thetreating solution canbe removed from the fibers by quenching and washingwith means which will stop thedifferential swelling, such as water.

Applicants have found that the critical factors in such treatment arethe rate of diffusion of the treating agent into the fiber, theconcentration of treating agent in the aqueous solution, the temperatureof the solution, the length of time during which the fibers are exposedto the treating solution and the amount of stress-free contractionallowed to the fibersduring treatment.

Applicants have found that {the concentration of treating agent in theaqueous solution should be sufficient to cause the treated fibers tocurl within a reasonable time, for example 30 minutes or less, butshould also be insufficient to dissolve the fiber or to swell the fibersat too fast a rate to allow control of the extent of curling anduncurling. When ketones are used, concentration of ketone in solutionwill generally be between about 95 percent and about percent, preferablybetween about 95 percent and about percent, by volume. When aqueousphenol solutions are used as textile treating solutions theconcentration of phenol in water should be between about 0-8 percent andabout to percent by volume, since between 8 and 85 percent phenolconcentration water and phenol form a twophase system which isunsuitable for use as a treating solution.

Treating agents having a difiusion rate into the fibers of less thanabout 0.l micron per second have been found to be acceptable, with adiffusion rate of less than abut 0.05 .microns per second beingpreferable and a rate of less than about 0.035 microns per second beingparticularly suitable.

Applicants have also found that, if treatment of the fibers is continuedbeyond the point at which they curl, after a relatively short time thefibers begin to uncurl and finally straighten 'out and the purpose oftreatment is defeated. Thus treatment should be continued only until thedesired degree of curling is achieved. In general, curling time shouldbe less than about 30 minutes;

it was found that curling time was a function of treating agentconcentration and also of temperature. lt-is difiicult to generalize asto relationship between concentration and curling and uncurling times;however, it has been observed that as temperature increases the lengthof time between curling and uncurling decreases.

Applicants have further found that, in order to control curling so as toachieve the desired degree of curling, the

fibers should be restrained in such a manner that they can undergostress-free contraction in an amount in the range from about 10 to about40 percent of their original length, preferably from about 15 to about25 percent. Such restraint can be achieved, for example, by looselywinding the fibers to be treated on a spool, allowing the desired about10 to about 40 percent slack in the winding.

Applicants have still further found that, after treating the fibersaccording to the process of this invention, further curling can beachieved by exposing the fibers to steam.

Although one skilled in the art can easily determine the optimumconcentration of treating agent in the treating solution, the optimumtreatment time, and the optimum amount of stress-free contraction byutilizing the above disclosure, specific examples of ranges of thesevalues for several suitable treating agents are given below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph illustrating theimproved properties of Dacron polyester fiber yarn (du Pont 70-l4-RO2-56multifilament yam) when treated with a 10:1 solution ofhexafluoroacetone trihydrate in water. 1t will be apparent thatconsiderable crimp has been efl'ected by the treatment of the yarn. Theyarn was treated for a period of about 9 minutes at room temperature.

FIGS. 2 and 3 illustrate the efi'ect of hexafluoroacetone trihydratetreatment of a single filament of Dacron polyester fiber.

FIG. 4 illustrates the effect of hexafiuoroacetone trihydrate treatmentof a Dacron Polyester yarn (du Pont's 70/ 1 4).

DESCRIPTION OF THE PREFERRED EMBODIMENT EXAMPLE 1 When hexafluoroacetonetrihydrate was used as the treating agent on Dacron polyester fibers,applicants found that it should be diluted with water in the range offrom about 8:1 to about 20:1 parts of treating agent per part of water.Above about 20:1 concentration curling and solution tended to occur atthe same time, while below about :1 concentration no tendency to curlwas observed after an exposure time as long as 130 minutes. Thepreferred range of concentration was found to be from about 12:1 toabout 8:1 parts of treating agent per part of water.

Table 1 below gives curling and uncurling times for Dacron polyesterfibers (du Ponts 70/ 14 Rotoset, Type 56) treated with variousconcentrations of hexafiuoroacetone trihydrate in water.

Table 2 below indicates the changes in fiber curling and un curlingtimes with increase in temperature for a :1 solution ofhesafiuoroacetone trihydrate in water using the same type of polyesterfiber described in the previous paragraph.

Table 2 Temperature "C. Curling Tilne Uncurling Time 22 5 min. 8 min. 42'1 Its 52 it (undetermlned) 65 M 4 EXAMPLE 2 Whenpentafluoromonochloroacetone trihydrate was used as the treating agenton the Dacron polyester fibers described in example 1 applicants foundthat the concentration of treating agent in water should be in the rangeof from about 5:1 to

about 20:1 parts of treating agent per part of water. The preferredrange of concentration was found to be from about 20:1 to about 7:1. Itwas found that exposure time for curling should be within the range ofabout 3 minutes for a 20 to 1 dilution to about 5% minutes for a 7:1dilution.

EXAMPLE 3 When tetrailuorodichloroacetone dihydrate was used as treatingagent on the Dacron polyester fibers described in example l, applicantsfound that its concentration should be within he range from about 10:1to about 3:1 parts of treating agent per part of water. The preferredrange of concentration was found to be from about 5:1 to about 3:1. itwas found that at 5 to 1 dilution curling time was about 3 minutes andat 3 to 1 dilution curling time was about 15% minutes and curling timeabout 22'minutes.

EXAMPLE 4 When phenol was used as the treating agent in aqueous solutionapplied to the Dacron polyester fibers described in example 1 applicantsfound that the curling and uncurling times for various concentrationswere as follows:

TABLE 3 Concentration of Phenol in aqueous Solution Curlng TimeUneurling Time 6% min. 3% 2% 8% 3 min. 2 93.5 1

l'lexafluoroacetone trihydrate and phenol were found to be the preferredtreating agents, since they exhibited little tendency to fibrillate thetreated yarns even at the extremes of concentration.

Table 4 below indicates that texturing by treatment with ketone hydratesis applicable to many types of polyester fibers.

TABLE 4 [Curling behavior of polyester yarnstin 6FK.3H0 at 10:1 dilutionwith we er Curling time, minutes Uncuriing tim Yam yp minutes CommentsDu Pont:

70-14-R02-55, bright 3044 70-34-R02-56 17 6-21 70-44-0-62du1L. H... '3

A 1 In 20 minutes, but curled in 1%, minutes and nncurlcd in 2% minutesin 20: 1 solution.

Loose curl.

. No curling.

While this invention has been described with particular reference to aspecific embodiment it is to be understood that it is not to be limitedthereto but is to be construed broadly and restricted solely by thescope of the appended claims.

We claim:

l. The process of curling polyester fibers which contacting the fiberswith an aqueous solution consisting essentially of from about 75 to 95percent by volume of a treating agent selected from the group consistingof a perfluorinated ketone hydrate and a perfluorochlorinated ketonehydrate having a diffusion rate into the fibers of less than about 0.1microns per second, at a temperature and for a period of time sufficientto cause differential swelling of the outer annular portions of thefibers with respect to the cores of the fibers, but not substantiallylonger than necessary to effect the desired degree of curling, whilemaintaining said fibers in a suficiently slack condition to permit astress-free contraction of from about to 40 percent of the originalfiber length.

2. The process of claim 1 wherein the aqueous solution consistsessentially of hexafluoroacetone trihydrate diluted with water in therange of from about 8:1 to about 2.:1 parts of her:- afluoroacetonetrihydrate per part of water.

3. The process of claim 2 wherein the aqueous solution contains fromabout 8:1 to about 12:1 parts of hexafluoroacetone trihydrate per partof water.

4. The process of claim 2 wherein the fibers are maintained in asufliciently slack condition to permit a stress-free contraction of fromabout 15 to about percent of the original fiber length.

5. The process of claim 2 wherein the curled fibers are subsequentlytreated by exposure to steam to effect further curling.

6. The process of claim 2 wherein the contact time is less than aboutminutes.

7. The process of claim 1 wherein the aqueous solution consistsessentially of pentafluoromonochloroacetone trihydrate diluted withwater in the range of from about 5:1 to about 20:1

parts of pentafluoromonochloroacetone trihydrate per part of water.

8. The process of claim 7 wherein the aqueous solution contains fromabout 7:1 to about 20:1 parts of pentafluoromonochloroacetone trihydrateper part of water.

9. The process of claim 7 wherein the fibers are maintained in asufiiciently slack condition to permit a stress-free contraction of fromabout 15 to about 25 percent of the original fiber length.

10. The process of claim 7 wherein the curled fibers are subsequentlytreated by exposure to steam to effect further curling.

11. The process of claim 7 wherein the contact time is less than about30 minutes.

12. The process of claim I wherein the aqueous solution consistsessentially of tetrafluorodichloroacetone dihydrate diluted with waterin the range of from about 3:1 to about 10:1 parts oftetrafiuorodichloroacetone dihydrate per part of water.

13. The process of claim 12 wherein the aqueous solution consistsessentially of tetrafluorodichloroacetone dihydrate diluted with waterin the range of from about 3:1 to about 5:1 parts oftetrafluorodichloroacetone dihydrate per part of water.

14. The process of claim 12 wherein the fibers are maintained in asufi'iciently slack condition to permit a stress-free contraction offrom about 15 to about 25 percent of the original fiber length.

15. The process of claim 12 wherein the curled fibers are subsequentlytreated by exposure to steam to eflect further curling.

H050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3620 666 Dated November 16 r 1971 Inventofls) Robert W. Lenz, Leo Barish,Virginia L. Lyons It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 69, that part of the formula which reads H O" should read3H 0 Column 1, line 70, that part of the formula which reads "CoCF Cl"should read COCF Cl Column 4, line 17, the word "he" should be the.

Claim 2, line 4, "2.:1" should be 20:1

Signed and sealed this 26th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

2. The process of claim 1 wherein the aqueous solution consistsessentially of hexafluoroacetone trihydrate diluted with water in therange of from about 8:1 to about 2.:1 parts of hexafluoroacetonetrihydrate per part of water.
 3. The process of claim 2 wherein theaqueous solution contains from about 8:1 to about 12:1 parts ofhexafluoroacetone trihydrate per part of water.
 4. The process of claim2 wherein the fibers are maintained in a sufficiently slack condition topermit a stress-free contraction of from about 15 to about 25 percent ofthe original fiber length.
 5. The process of claim 2 wherein the curledfibers are subsequently treated by exposure to steam to effect furthercurling.
 6. The process of claim 2 wherein the contact time is less thanabout 30 minutes.
 7. The process of claim 1 wherein the aqueous solutionconsists essentially of pentafluoromonochloroacetone trihydrate dilutedwith water in the range of from about 5:1 to about 20:1 parts ofpentafluoromonochloroacetone trihydrate per part of water.
 8. Theprocess of claim 7 wherein the aqueous solution contains from about 7:1to about 20:1 parts of pentafluoromonochloroacetone trihydrate per partof water.
 9. The process of claim 7 wherein the fibers are maintained ina sufficiently slack condition to permit a stress-free contraction offrom about 15 to about 25 percent of the original fiber length.
 10. Theprocess of claim 7 wherein the curled fibers are subsequently treated byexposure to steam to effect further curling.
 11. The process of claim 7wherein the contact time is less than about 30 minutes.
 12. The processof claim 1 wherein the aqueous solution consists essentially oftetrafluorodichloroacetone dihydrate diluted with water in the range offrom about 3:1 to about 10:1 parts of tetrafluorodichloroacetonedihydrate per part of water.
 13. The process of claim 12 wherein theaqueous solution consists essentially of tetrafluorodichloroacetonedihydrate diluted with water in the range of from about 3:1 to about 5:1parts of tetrafluorodichloroacetone dihydrate per part of water.
 14. Theprocess of claim 12 wherein the fibers are maintained in a sufficientlyslack condition to permit a stress-free contraction of from about 15 toabout 25 percent of the original fiber length.
 15. The process of claim12 wherein the curled fibers are subsequently treated by exposure tosteam to effect further curling.